Use new RegionSelector for Partial Event Building

Follow-up from !36883 (merged) and RegionSelector migration in general (ATR-19657) -- fully migrate TrigPartialEventBuilding.

The migration simplifies the code, which is great to see. The specific changes made:

1. Use ToolHandleArray of RegSelTools in RoIPEBInfoWriterTool and provide helper function to configure them. The updated configuration calls the RegSelToolConfig functions directly so there is no need to introduce any extra Enums - the function names from RegSelToolConfig.py serve as an Enum.
2. Adapt the configuration of the clients in TriggerMenuMT and TrigP1Test.
3. Fix handle initialisation in RegSelTool - if a handle is not intended for use, it should be initialised with false passed in the argument. Otherwise, such configuration leads to scheduler stalls.

It seems !36883 (merged) or something else recently broke the PEB code as I was not seeing all ROBs being added in the latest nightly. Not sure what exactly was broken, but this MR restores the PEB ROB lists that are produced with Athena 22.0.18. I was checking this by comparing debug output of the RoIPEBInfoWriterTool from test_trigP1_PEB_DS_build.py.

cc @sutt